The field of the invention is aircraft survivability to infrared missiles. More specifically, the invention provides vulnerability reduction (hit acceptance) by coaxing missiles away from critical aircraft components and toward sacrificial structure using an infrared decoy.
Conventional, prior art, vulnerability reduction techniques such as onboard fire extinguishers, reticulated foam, and damage resistant structures applied to present-day aircraft generally provide a reasonable level of protection against, respectively, fuel fires, ullage explosions, and hydrodynamic ram caused by bullets and individual missile fragments. However, as presently applied, these vulnerability reduction features cannot be considered fully capable of insuring aircraft survivability against the direct hits of shoulder-launched Man Portable Air Defense System (MANPADS) missiles. Conventional vulnerability reduction features are often overmatched by the hit-to-kill MANPADS munitions containing ten-times the explosive charge weight of common anti-aircraft artillery (AAA) munitions and up to 100-times the mass.
In recent years, the infrared MANPADS threat has been widely proliferated throughout the world. Attempts to achieve aircraft survivability in response to MANPADS have commonly centered on susceptibility reduction (hit avoidance) features. A prior-art susceptibility reduction feature is the towed RF (radar) decoy. The tow-cable length is set long enough so that the aircraft is outside the kill radius for any missile detonating near the decoy. A towed decoy, however, has several limitations. While surface-to-air missiles (SAMs) may be guided to the RF decoy, the missile's proximity fuse may, by chance, detonate between the aircraft and decoy, causing an aircraft kill. Although the tow cable can be made longer to avoid such a problem, weight and on-board volumetric storage requirements become an issue. Further, regardless of cable length, aircraft operating at low altitudes will attract barrages of AAA fire. Although susceptibility reduction philosophy emphasizes avoiding detection and avoiding a hit, an RF (or dumb IR) decoy will attract continuous attention from a variety of SAM and AAA systems. Under low-altitude circumstances, hits may therefore occur with a high degree of frequency.
An example prior-art operational vulnerability reduction system is the sacrificial engine-nozzle extension applied several years ago to Israeli A-4 aircraft. IR-seeking missiles attracted to this hot-spot location destroyed only the sacrificial extension. Flight-critical engine components were protected. Limitations of the nozzle extension concept are that 1) the sacrificial extension can involve considerable weight, 2) the cost of retrofit on most aircraft types is prohibitively high, 3) the extension is not easily adapted to thrust vectoring aircraft, 4) without an extremely long nozzle extension the aircraft's empennage may remain susceptible to damage, 5) the nozzle extension can increase beam-aspects of the aircraft's thermal signature, and 6) missiles approaching directly from the rear can retain sufficient forward kinetic energy to damage critical engine components.
While prior art MANPADS has focused on hit avoidance, aircraft encounters with MANPADS throughout the past 40 years have clearly demonstrated that hit avoidance is not always possible. Furthermore, aircraft flying at extreme altitudes to avoid missile hits may result in mission compromise.
As an alternative or in addition to vulnerability reduction including hit avoidance features is vulnerability reduction including hit acceptance features. The method and device of the invention involves a decoy infrared lamp installed on a sacrificial support structure. Together, they will increase aircraft survivability to MANPADS missile hits by protecting the targeted aircraft's most critical components. The invention also provides susceptibility reduction in that approaching missiles are coaxed away from the aircraft's most critical zones.